Researchers break throughput record for LiFi communications

CEA-Leti researchers have broken the throughput world record of 5.1Gbps in visible light communications (VLC) using a single GaN blue micro-LED. Their data transmission rate of 7.7Gbps achieved with a 10µm microLED signals another step toward commercialisation and widespread use of LiFi communication.

VLC, commonly called LiFi, is an emerging wireless communication system that provides an alternative or a complementary technology to RF systems such as WiFi and 5G. It is deemed to be a promising technology for security-related applications as light propagation can be restricted to a room with no information leakage, as opposed to WiFi communication, which penetrates walls. LiFi also holds hope for ultra-highspeed data transmission in environments where RF emissions are controlled, such as hospitals, schools, and aircraft.

“This technology has exciting potential for mass-market applications,” said Benoit Miscopein, CEA-Leti research scientist. “Multi-LED systems could replace WiFi, but wide-scale adoption will require a standardisation process to ensure the systems’ interoperability between different manufacturers. The Light Communications Alliance was created in 2019 to encourage the industry to implement this standardisation.”

As well as a stand-alone WiFi-like standard, the opportunity to incorporate this new technology as a component carrier in the downlink of 5G-NR is also being investigated to bring a large additional license-free bandwidth.

“This may be feasible because CEA-Leti’s LiFi physical layer relies on the same concepts as WiFi and 5G technologies,” said Miscopein. “Matrices of thousands of micro-LEDs could also open the way to mid- to long-range applications, such as indoor wireless multiple access.”

Defending the bandwidth of each microLED within a matrix demands that each signal is generated as close as possible to the micro-optical source.

“To meet this challenge, we expect to hybridize the microLED matrix onto another matrix of CMOS drivers: one simple CMOS driver will pilot one microLED,” Miscopein said. “This will also enable the additional feature of piloting each microLED pixel independently, and that allows new types of digital-to-optical waveforms that could eliminate the need for digital-to-analog converters commonly used in the conventional ‘analogue’ implementations of LiFi.”